Nanostructural and piezoelectric characterization of electro-formed δ-phase poly(vinylidene fluoride) thin films

Abstract

Ferroelectric polymer PVDF possesses different polymorphs. Solution-processed thin films crystallize mostly into the paraelectric α-phase. From α-PVDF, the electroactive phases β-, γ-, δ-PVDF can be achieved by further treatments. For instance, δ-PVDF, also known as α p-phase, can be obtained by electro-forming. In this work, we study the α-PVDF surface morphology using atomic force microscopy through a high-resolution image at the sub-nanometre scale. We go through the ferro- and piezoelectric properties of the electro-formed δ-PVDF thin films and we present an electro-mechanical characterization in high-fields regime, for studying the non-linear electrostrain behaviour, and in low-fields regime, for extracting the piezoelectric coefficient.